Sweet and Sauer - Issue #16 - 2022

The subscriber-only newsletter for the week of April 23rd, 2022.

Sweet and Sauer - Issue #16 - 2022

Next Generation Squad Weapon System Contract Awarded to Sig Sauer

The Army's new M5 and M250

THIS WEEK, the US Army announced that Sig Sauer won the 10-year contract to furnish the next generation of squad weapons systems. The Sig MCX-SPEAR and Sig NGSW-AR will replace the M4 and M249, eventually becoming the M5 and M250, respectively. This is a pretty big deal, and we'll look at why after the official press release:

WASHINGTON – The U.S. Army announced today the award of a 10-year firm-fixed-price follow-on production contract to Sig Sauer for the manufacture and delivery of two Next Generation Squad Weapon variations (the XM5 Rifle and the XM250 Automatic Rifle) and the 6.8 Common Cartridge Family of Ammunition.
This award was made following a rigorous 27-month prototyping and evaluation effort that included numerous technical tests and Soldier touch points of three competing prototype systems. The value of the initial delivery order on the contract is $20.4 million for weapons and ammunition that will undergo testing. The contract includes accessories, spares and contractor support. It also provides the other Department of Defense services and, potentially, Foreign Military Sales countries the opportunity to purchase the NGSW weapons.
The XM5 Rifle will replace the M4/M4A1 carbine within the close combat force, and the XM250 Automatic Rifle is the planned replacement for the M249 Squad Automatic Weapon Both weapons provide significant capability improvements in accuracy, range and overall lethality. They are lightweight, fire more lethal ammunition, mitigate recoil, provide improved barrel performance, and include integrated muzzle sound and flash reduction.
Both weapons fire common 6.8 millimeter ammunition utilizing government provided projectiles and vendor-designed cartridges. The new ammunition includes multiple types of tactical and training rounds that increase accuracy and are more lethal against emerging threats than both the 5.56mm and 7.62mm ammunition.
The XM5 and XM250 will be paired with the XM157 Fire Control, a ruggedized advanced fire control system that increases accuracy and lethality for the close combat force. The XM157 integrates a number of advanced technologies, including a variable magnification optic (1X8), backup etched reticle, laser rangefinder, ballistic calculator, atmospheric sensor suite, compass, Intra-Soldier Wireless, visible and infrared aiming lasers, and a digital display overlay. It is produced by Sheltered Wings Inc. d/b/a Vortex Optics, Barneveld, Wisconsin.

Key Changes


The most significant change is moving away from the 5.56MMx45 NATO cartridge to the larger 6.8MMx51 Cartridge. The 6.8MM (aka 277 Fury) is a hybrid cartridge that features a steel base and brass case body. The stronger steel base lets the round safely operate at a whopping 80,000PSI chamber pressure (5.56 ammo usually runs ~ 55,000-62,000PSI). The case itself is the same diameter and length as the 7.62MM NATO.

.277 Fury hybrid ammo (note the steel base and brass case body)

The 6.8MM was selected to mitigate the performance limitations of the 5.56MM NATO round and boasts better range and enhanced lethality compared to the older and smaller cartridge. This will be the first time the Army has adopted a new round at scale in over 60 years.

Sig's 6.8mm x 51 / .277 Fury | Source: NorCal Gun Vault

Basic Comparison

The 6.8MM x 51 carries more energy and moves more quickly than the 7.62MM NATO round and doubles the 5.56MM NATO round energy. Sig claims the new cartridge is a better performer at a distance than even the respected 6.5mm Creedmoor round.

Cartridge Grain Weight Muzzle Velocity Energy
5.56MM x 45 (M855A1) 62GR 3,150 FPS 1,371 ft-lbs
6.8MM x 51 (Match) 135GR 3,000 FPS 2,694 ft-lbs
7.62MM x 51 (M80) 147GR 2,800 FPS 2,559 ft-lbs

Signature Reduction

By default, both the M5 and M250 will be paired with Sig SLX suppressors. From Sig's press release: